In recent years, a SiC semiconductor device has drawn attention, which is mainly used for systems in various fields related to power electronics such as a motor control system, a power conversion system and so forth.
A patent literature 1 discloses a vertical IGBT, which includes an n-type drift layer formed on a SiC substrate, a p-type base region formed on the upper portion of the drift layer, and an n-type emitter region formed on the upper portion of the base region.
A patent literature 2 discloses a trench gate MOSFET that includes an n+ type SiC substrate, an n− type base layer formed on the SiC substrate, a p-type body region formed in the surface portion of the base layer, an n+ type source region formed in the surface portion of the body region, a gate trench passing through the source region and the body region from the surface of the base layer, and a gate electrode embedded in the gate trench across a gate insulating film.